Jon Pop Posted October 25, 2015 Share #1 Posted October 25, 2015 Advertisement (gone after registration) Just curious for some history from all the great Barnack historians out there. I have a iiif RD ST (SN 719###, 1954) and the main shutter dial has 25-1 (with then of course 1/25 and slow speeds on the slow speed dial), while my friend has an older iiif BD, no ST (1951, SN 548 ###) and it runs 30-1. Which is what my iiig has as well for the setting to switch to the slow speed dial. Just curious as to why the difference...I'd have thought it would have been the other way around, i.e. the later models would have used 1/30 as flash synch, etc. got better. Was trying to find some information, we were just comparing notes on the phone and chatting about it and I thought I'd ask the Forum Sages and embarrass myself by revealing my limited knowledge in the process. Quote Link to post Share on other sites More sharing options...
Advertisement Posted October 25, 2015 Posted October 25, 2015 Hi Jon Pop, Take a look here iiif Shutter Speed dials and variations question. I'm sure you'll find what you were looking for!
jerzy Posted October 25, 2015 Share #2 Posted October 25, 2015 With introduction of IIIc shutter has been improved, this allowed to have full frame opened at 1/30 compared to 1/20 in previous models. Around 1954 when Leica switched to international speeds the 1/25 was used. Interesting detail is that red dial IIf, without slow speed dial still were equipped with slow speed mechanism to build 1/25. 1 Quote Link to post Share on other sites More sharing options...
luigi bertolotti Posted October 25, 2015 Share #3 Posted October 25, 2015 (edited) Yes... the 1/25 of later RD vs. 1/30 of the older BD can look an oddity... but they made like this, period... ; anyway... it can be seen as a step-by-step evolution towards the geometrical progression that entered in IIIG (and is the usual today) ... apart B, in the range 1 to 1/1000 the BD has 13 times, the RD 12, the IIIG 11... maybe years and years ago it was considered a plus to have lot of times to choose... the handeld meters had too a lot of them... it took a certain time to get users accustomed to the fact that the equivalence "1 time slower / 1 stop closed = same exposure" is the easiest to deal with. Making a bit of hair-splitting... ... one could speculate that the shift towards times in geometrical progression is someway related to the shift towards diaphragm rings evenly spaced (degrees of rotation from 1 stop to the next one) : they allow an easier setting of "intermediate f stop" so that, with the std. modern time scale, you have an easy control when you whish a 1/2 EV tuning... onto an old Elmar 90, just as an example, you could easily set a fstop half between 4 and 5,6.... but between 22 and 32 the tolerancing was critical... Edited October 25, 2015 by luigi bertolotti 1 Quote Link to post Share on other sites More sharing options...
Jon Pop Posted October 25, 2015 Author Share #4 Posted October 25, 2015 Fascinating stuff...! I can imagine there were probably many heated debates in the design/production group about which settings and why. I think I have an issue with the "5" setting on the slow dial. It sounds way too fast compared to 10 and 15. In fact, when I first shoot at 10 or 15, and go to 5, it sounds more accurate, but when I wind and then shoot it again, it is faster. Everything else seems great though (so far...have to process the test roll....), just might be time for an adjustment. Quote Link to post Share on other sites More sharing options...
jerzy Posted October 25, 2015 Share #5 Posted October 25, 2015 Sounds like a typical issue with slow speeds, cleaning should cure it. However I suppose you might have similar issue with all slow speed, in particular it may be observed with 1sec: shoot, wind quickly and shoot again. Second time it should be noticeably faster -slow sped mechanism does not return to initial position. There could be as well another reason, misalignment of coupling with 2nd shutter curtain however the dirt is most common. Quote Link to post Share on other sites More sharing options...
iphoenix Posted October 29, 2015 Share #6 Posted October 29, 2015 I have the same problem with a Canon 7.shutter. Set it to 1/8 and it's around 1/30, with all the other speeds seeming correct. I've been told a shutter service is needed, but I prefer to use my Leicas so can't justify the cost. I suggest the problem with yours will only become more frequent if allowed to continue. Quote Link to post Share on other sites More sharing options...
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